Rositza Betcheva - Academia.edu (original) (raw)
Papers by Rositza Betcheva
Dyes and Pigments, Jul 1, 1998
ABSTRACT
Dyes and Pigments, Jul 1, 2013
A new 4-(2-N,N-dimethylamino)ethylamino-N-2-hydroxyethyl-1,8-naphthalimide has been synthesized. ... more A new 4-(2-N,N-dimethylamino)ethylamino-N-2-hydroxyethyl-1,8-naphthalimide has been synthesized. The photophysical characteristics have been determined in aqueous and acetonitrile solutions. The influence of metal cations (Ni 2þ , Zn 2þ , and Cu 2) and protons on the fluorescence intensity has been studied to evaluate the capacities of the newly synthesized 1,8-naphthalimide as a fluorescence sensor. The 1,8naphthalimide dye has been chemically bonded to a cotton textile fabric in order to obtain a heterogeneous fluorescent sensor for detecting of metal cations and protons.
Current Medicinal Chemistry, Oct 1, 2012
The review presents fluorescence spectroscopic studies on the capacities of newly synthesized pol... more The review presents fluorescence spectroscopic studies on the capacities of newly synthesized polypropyleneamine and polyamidoamine fluorescent dendrimers to detect biologically important metal ions. It has been shown that those fluorescent dendrimers whose periphery comprises 1,8-napthalimide fragments are highly sensitive to metal ions which are of great importance to the living organisms.
NATO science for peace and security series, 2010
The mycotoxins are biological pollutants. They are toxic metabolites produced by several fungi in... more The mycotoxins are biological pollutants. They are toxic metabolites produced by several fungi in foods and feeds. They are probably the best known and most intensively examined mycotoxins in the world. Contamination of foods with mycotoxines can be also object of bioterrorism. Mycotoxins are non-volatile, relative low-weight molecules secondary metabolic products that may affect exposed persons in a variety of ways. These compounds are considered secondary metabolites because they are not necessary for fungal growth and are simply a product of the primary metabolic processes. The functions of mycotoxins have not been totally studied, but it is established that they play a key role in the antagonistic processes concerning microorganisms from the same environment. They are also believed to help parasitic fungi invade host tissues. The amount of toxins needed to produce adverse health effects varies widely among toxins, as well as to each person’s immune system. The aim of the present review is to present development of new biosensors for mycotoxines determination in foods, utilizing new polymeric membranes with immobilized enzymes and antibodies. The following investigations concerning biosensors design are presented investigations concerning smart polymer characteristics, based on new synthesized polymers and dendrimers; simultaneously immobilization of mediators, fluorescent dyes and biochemical recognition molecules; amperometric and optical sensors constructions; investigations of the main parameters as a response time, linear range, reproducibility; mathematical models concerning optimization of biosensor measurements are described and compared with standard methods as HPLC and ELISA.
Macromolecular Materials and Engineering, Dec 1, 2003
Polymer Degradation and Stability, Oct 1, 2006
The colouristic and fluorescent characteristics of a new composite material based on a PAMAM dend... more The colouristic and fluorescent characteristics of a new composite material based on a PAMAM dendrimer of second generation whose periphery is modified with 4-N,N-dimethylaminoethylamino-1,8-naphthalimide and polyamide-6 have been investigated. This dendrimer has been investigated with regard to its application as a heterogenic sensor capable of detecting metal cations and protons in aqueous solutions. In the presence of metal cations (Ni 2þ , Fe 2þ , Fe 3þ and Co 2þ) and protons the fluorescence intensity of the composite increases due to their coordination with dendrimer molecule. The results obtained reveal the capacity of this system to act as a sensitive sensor of environmental pollution by metal cations and protons. It has been shown that in N,N-dimethylformamide solution the metal cations inhibit the processes of photodegradation of the dendrimer.
Journal of Applied Polymer Science, 2007
The pH indicator proposed is a water-soluble dye based on benzo[de]antracen-7-one. Dissolving in ... more The pH indicator proposed is a water-soluble dye based on benzo[de]antracen-7-one. Dissolving in buffered aqueous solution, it changes color from yellow to orange and in the mean time decreases its fluorescence emission as a function of the amine concentration. Viscose fabric, dyed with the same dye has been investigated as a new reversible colorimetric and fluorescent sensor material for ammonia and aliphatic amines in buffered solution. The high value of the dye pK a and the influence of the textile matrix on the selective detection of dimethylamine compared to ammonia, trimethylamine, and metylamine have been studied. The different response of the solution and textile matrix as well as the optical analyses both as a color change and a fluorescence emission have been discussed. The advantage of this sensor is the fact that depending on the analytical problem to be solved and the available instrumentation it can be used either as a fluorogenic or as a chromogenic chemosensor. In addition, the textile sensor is characterized by facile fabrication, low cost, sensibility, and reproducibility.
![Research paper thumbnail of Synthesis and functional properties of new optical pH sensor based on benzo[de]anthracen-7-one immobilized on the viscose](https://attachments.academia-assets.com/118653567/thumbnails/1.jpg)
](Dyes and Pigments, 2007
The synthesis of a new pH sensor based on the fluorescent water-soluble 1-[(7-oxo-7H-benzo[de]ant... more The synthesis of a new pH sensor based on the fluorescent water-soluble 1-[(7-oxo-7H-benzo[de]anthracen-3-ylcarbamoyl)-methyl]-pyridinium chloride is described. The molecule displays colour change from yellow to orange-reddish as a function of pH in aqueous solution. Viscose fabric could be used as a planar sensor for the visualization of pH gradients via imaging in two dimensions over large surfaces with highly local resolution. The results from colour measurement showed that the dyed viscose fabric is suitable for ''naked eye'', on-line, reversible solid-state pH sensor in the alkaline region.
Current Opinion in Biotechnology, Sep 1, 2011
Dyes and Pigments, Oct 1, 1999
Eleven unsaturated triazinylstilbene¯uorescent brightening agents were synthesized. They were cap... more Eleven unsaturated triazinylstilbene¯uorescent brightening agents were synthesized. They were capable of copolymerization with styrene and acrylonitrile, giving colourless¯uorescent polymers having good stability to wet treatments and solvents. The spectral and thermal properties, brightening eect on cotton and CIE coordinates were evaluated.
Journal of Photochemistry and Photobiology A-chemistry, Sep 1, 2006
The photophysical characteristics of a new water-soluble fluorescent pH sensitive 1-[(7-Oxo-7H-be... more The photophysical characteristics of a new water-soluble fluorescent pH sensitive 1-[(7-Oxo-7H-benzo [de] anthracen-3-ylcarbamoyl)-methyl]-pyridinium chloride based on ICT (internal charge transfer) are described.“On-off” switching of fluorescence as a function of pH in ...
Journal of Photochemistry and Photobiology A-chemistry, Aug 1, 2001
The copolymerization of methylmethacrylate (MMA) with 1,8-naphthalimide fluorescent brighteners (... more The copolymerization of methylmethacrylate (MMA) with 1,8-naphthalimide fluorescent brighteners (fluorophores) yielding transparent blue fluorescent side-group copolymers has been investigated. It has been found that more than 0.92% of the fluorophores are chemically bonded to the polymer chain. Changes occurring in the chromophoric systems of the fluorophores during copolymerization have not been detected. The effect of polymer modification has been proved by an appropriate spectrophotometric method. The influence of the studied monomeric 1,8-naphthalimide fluorescent brighteners upon the photostability of the structurally bleached polymethylmethacrylate has been determined.
European Journal of Chemistry, Mar 31, 2010
New eco-labels for textile products and demands to wastewater discharges are forcing wool scourin... more New eco-labels for textile products and demands to wastewater discharges are forcing wool scouring processes to reuse wastewater and to search for more efficient and environmental friendly methods of processing. This challenge has prompted intensive research in new advanced treatment technologies. Due to the high level of detergent usage, the most widely used treatment of wool scouring effluent (WSE) is anaerobic. As the pressure to use more environmentally acceptable treatment methods increases there is the need to study alternative, biologically efficient treatment systems for WSE. This work aims at studying the influence of the combined enzymatic-ultrasound scouring of raw wool fibers on the effectiveness of the anaerobic treatment of effluents from this processing. Experiments carried out combined enzyme and ultrasound scouring of wool followed by treatment of effluents obtained. Aerobic and anaerobic treatments of these effluents were performed using a special laboratory reactor. Chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of effluents from different scouring processes were defined. The results of this study indicate that the anaerobic biological and chemical treatments of WSE treated by combined enzymatic-ultrasound scouring is a promising alternative technology from the point of view of reducing the wastewater pollution and the effective cleaning of effluents coming out from this process. Wool scouring effluent Aerobic treatment Anaerobic treatment Clean technology Activated-sludge Enzyme
Journal of Biomaterials and Nanobiotechnology, 2011
Scouring of raw wool is a chemical treatment that needs a high amount of detergents, alkalis and ... more Scouring of raw wool is a chemical treatment that needs a high amount of detergents, alkalis and water. Effluents produced by this treatment are extremely polluted with chemicals and impurities washed out from the fibers. It is well known that the ultrasound washing can remove effectively different substances from the textile surfaces even without surfactants due to the cavitations occurring at certain parameters of the ultrasound field. On the other side water treatments of wool combined with mechanical agitation provoked felting which can impair the quality of wool materials. Felting itself depends not only on the parameters of water treatments but also on the structure of wool cuticle. Partial hydrolysis of the cuticle with some proteases can decrease considerably the wool felting. The aim of this work is to study the possibility of applying the ultrasound at the process of raw wool scouring and the influence of proteases on the felting properties of wool at these conditions. It has been found out that ultrasound environment applied does not impair the specific activity of enzyme auxiliaries used and leads to increasing of their effect on the surface of wool fibers. Thus the scouring process studied could be used for developing of a technology producing lower amount and less polluted effluents.
BioResources, 2007
Research on lignin biodegradation has become of great interest, due to the fact that lignin is on... more Research on lignin biodegradation has become of great interest, due to the fact that lignin is one of the most abundant renewable materials, next to cellulose. Lignin is also the substance that gives color to raw flax fibers. In order to bleach the flax and to keep its tenacity high enough for textile applications, it is necessary to remove the lignin and partially to preserve the pectin. Lignin and pectin are the main constituents of the layer which sticks the flax cells together within the multicellular technical fiber. White-rot fungi and their oxidative enzymes, laccases and peroxid-ases (lignin peroxidases and manganese peroxidases), are being applied for the biobleaching of papermaking pulp, thereby reducing the need for environmentally harmful chemicals. Some data also suggest that it is possible to use other phenolytic enzymes, such as pure laccase, for this purpose. The objective of the present work was to study the possibility of bleaching flax fibers by pure laccase and c...
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2008
The investigations aim at revealing the ability of a 1,8-napthalimide-modified poly(amidoamine) d... more The investigations aim at revealing the ability of a 1,8-napthalimide-modified poly(amidoamine) dendrimer from second generation to respond to the presence of cuprum cations and protons in the environment. It has been established that a single Cu 2+ cation present in the dendrimer molecule is capable of quenching more than 78% of its fluorescence what is an indication of high sensitiveness. An enhancement of the fluorescence emission of the dendrimer has been observed in acidic medium. It has been established that the processes of coordinating the ions in different sites of the dendrimer are reversible.
Macromolecular Materials and Engineering, 2002
Macromolecular Materials and Engineering, 2003
Journal of Applied Polymer Science, 2001
The copolymerization of styrene or methyl methacrylate with 1,8‐naphthalimide dyes to yield fluor... more The copolymerization of styrene or methyl methacrylate with 1,8‐naphthalimide dyes to yield fluorescent side‐group copolymers was investigated. During copolymerization, no changes occurred in the chromophoric systems of the dyes. Colorimetrically, it was found that more that 0.90% of the dyes were chemically bonded to the polymer chain. The effect of polymer coloration was proven by appropriate coloristic characterization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2463–2470, 2001
International Journal of Clothing Science and Technology, 1999
In this study the effect of the aminofunctional silicone softeners on fabrics’ heat and moisture ... more In this study the effect of the aminofunctional silicone softeners on fabrics’ heat and moisture transport properties has been investigated by means of Alambeta and Permetest instruments. The silicone treated PES blended fabrics are warmer to the touch, but less comfortable as regards their reduced water‐vapour permeability. The finishing stage of the fabrics has considerable influence on their thermal touch sensation and water‐vapour permeability.
Dyes and Pigments, Jul 1, 1998
ABSTRACT
Dyes and Pigments, Jul 1, 2013
A new 4-(2-N,N-dimethylamino)ethylamino-N-2-hydroxyethyl-1,8-naphthalimide has been synthesized. ... more A new 4-(2-N,N-dimethylamino)ethylamino-N-2-hydroxyethyl-1,8-naphthalimide has been synthesized. The photophysical characteristics have been determined in aqueous and acetonitrile solutions. The influence of metal cations (Ni 2þ , Zn 2þ , and Cu 2) and protons on the fluorescence intensity has been studied to evaluate the capacities of the newly synthesized 1,8-naphthalimide as a fluorescence sensor. The 1,8naphthalimide dye has been chemically bonded to a cotton textile fabric in order to obtain a heterogeneous fluorescent sensor for detecting of metal cations and protons.
Current Medicinal Chemistry, Oct 1, 2012
The review presents fluorescence spectroscopic studies on the capacities of newly synthesized pol... more The review presents fluorescence spectroscopic studies on the capacities of newly synthesized polypropyleneamine and polyamidoamine fluorescent dendrimers to detect biologically important metal ions. It has been shown that those fluorescent dendrimers whose periphery comprises 1,8-napthalimide fragments are highly sensitive to metal ions which are of great importance to the living organisms.
NATO science for peace and security series, 2010
The mycotoxins are biological pollutants. They are toxic metabolites produced by several fungi in... more The mycotoxins are biological pollutants. They are toxic metabolites produced by several fungi in foods and feeds. They are probably the best known and most intensively examined mycotoxins in the world. Contamination of foods with mycotoxines can be also object of bioterrorism. Mycotoxins are non-volatile, relative low-weight molecules secondary metabolic products that may affect exposed persons in a variety of ways. These compounds are considered secondary metabolites because they are not necessary for fungal growth and are simply a product of the primary metabolic processes. The functions of mycotoxins have not been totally studied, but it is established that they play a key role in the antagonistic processes concerning microorganisms from the same environment. They are also believed to help parasitic fungi invade host tissues. The amount of toxins needed to produce adverse health effects varies widely among toxins, as well as to each person’s immune system. The aim of the present review is to present development of new biosensors for mycotoxines determination in foods, utilizing new polymeric membranes with immobilized enzymes and antibodies. The following investigations concerning biosensors design are presented investigations concerning smart polymer characteristics, based on new synthesized polymers and dendrimers; simultaneously immobilization of mediators, fluorescent dyes and biochemical recognition molecules; amperometric and optical sensors constructions; investigations of the main parameters as a response time, linear range, reproducibility; mathematical models concerning optimization of biosensor measurements are described and compared with standard methods as HPLC and ELISA.
Macromolecular Materials and Engineering, Dec 1, 2003
Polymer Degradation and Stability, Oct 1, 2006
The colouristic and fluorescent characteristics of a new composite material based on a PAMAM dend... more The colouristic and fluorescent characteristics of a new composite material based on a PAMAM dendrimer of second generation whose periphery is modified with 4-N,N-dimethylaminoethylamino-1,8-naphthalimide and polyamide-6 have been investigated. This dendrimer has been investigated with regard to its application as a heterogenic sensor capable of detecting metal cations and protons in aqueous solutions. In the presence of metal cations (Ni 2þ , Fe 2þ , Fe 3þ and Co 2þ) and protons the fluorescence intensity of the composite increases due to their coordination with dendrimer molecule. The results obtained reveal the capacity of this system to act as a sensitive sensor of environmental pollution by metal cations and protons. It has been shown that in N,N-dimethylformamide solution the metal cations inhibit the processes of photodegradation of the dendrimer.
Journal of Applied Polymer Science, 2007
The pH indicator proposed is a water-soluble dye based on benzo[de]antracen-7-one. Dissolving in ... more The pH indicator proposed is a water-soluble dye based on benzo[de]antracen-7-one. Dissolving in buffered aqueous solution, it changes color from yellow to orange and in the mean time decreases its fluorescence emission as a function of the amine concentration. Viscose fabric, dyed with the same dye has been investigated as a new reversible colorimetric and fluorescent sensor material for ammonia and aliphatic amines in buffered solution. The high value of the dye pK a and the influence of the textile matrix on the selective detection of dimethylamine compared to ammonia, trimethylamine, and metylamine have been studied. The different response of the solution and textile matrix as well as the optical analyses both as a color change and a fluorescence emission have been discussed. The advantage of this sensor is the fact that depending on the analytical problem to be solved and the available instrumentation it can be used either as a fluorogenic or as a chromogenic chemosensor. In addition, the textile sensor is characterized by facile fabrication, low cost, sensibility, and reproducibility.
Dyes and Pigments, 2007
The synthesis of a new pH sensor based on the fluorescent water-soluble 1-[(7-oxo-7H-benzo[de]ant... more The synthesis of a new pH sensor based on the fluorescent water-soluble 1-[(7-oxo-7H-benzo[de]anthracen-3-ylcarbamoyl)-methyl]-pyridinium chloride is described. The molecule displays colour change from yellow to orange-reddish as a function of pH in aqueous solution. Viscose fabric could be used as a planar sensor for the visualization of pH gradients via imaging in two dimensions over large surfaces with highly local resolution. The results from colour measurement showed that the dyed viscose fabric is suitable for ''naked eye'', on-line, reversible solid-state pH sensor in the alkaline region.
Current Opinion in Biotechnology, Sep 1, 2011
Dyes and Pigments, Oct 1, 1999
Eleven unsaturated triazinylstilbene¯uorescent brightening agents were synthesized. They were cap... more Eleven unsaturated triazinylstilbene¯uorescent brightening agents were synthesized. They were capable of copolymerization with styrene and acrylonitrile, giving colourless¯uorescent polymers having good stability to wet treatments and solvents. The spectral and thermal properties, brightening eect on cotton and CIE coordinates were evaluated.
Journal of Photochemistry and Photobiology A-chemistry, Sep 1, 2006
The photophysical characteristics of a new water-soluble fluorescent pH sensitive 1-[(7-Oxo-7H-be... more The photophysical characteristics of a new water-soluble fluorescent pH sensitive 1-[(7-Oxo-7H-benzo [de] anthracen-3-ylcarbamoyl)-methyl]-pyridinium chloride based on ICT (internal charge transfer) are described.“On-off” switching of fluorescence as a function of pH in ...
Journal of Photochemistry and Photobiology A-chemistry, Aug 1, 2001
The copolymerization of methylmethacrylate (MMA) with 1,8-naphthalimide fluorescent brighteners (... more The copolymerization of methylmethacrylate (MMA) with 1,8-naphthalimide fluorescent brighteners (fluorophores) yielding transparent blue fluorescent side-group copolymers has been investigated. It has been found that more than 0.92% of the fluorophores are chemically bonded to the polymer chain. Changes occurring in the chromophoric systems of the fluorophores during copolymerization have not been detected. The effect of polymer modification has been proved by an appropriate spectrophotometric method. The influence of the studied monomeric 1,8-naphthalimide fluorescent brighteners upon the photostability of the structurally bleached polymethylmethacrylate has been determined.
European Journal of Chemistry, Mar 31, 2010
New eco-labels for textile products and demands to wastewater discharges are forcing wool scourin... more New eco-labels for textile products and demands to wastewater discharges are forcing wool scouring processes to reuse wastewater and to search for more efficient and environmental friendly methods of processing. This challenge has prompted intensive research in new advanced treatment technologies. Due to the high level of detergent usage, the most widely used treatment of wool scouring effluent (WSE) is anaerobic. As the pressure to use more environmentally acceptable treatment methods increases there is the need to study alternative, biologically efficient treatment systems for WSE. This work aims at studying the influence of the combined enzymatic-ultrasound scouring of raw wool fibers on the effectiveness of the anaerobic treatment of effluents from this processing. Experiments carried out combined enzyme and ultrasound scouring of wool followed by treatment of effluents obtained. Aerobic and anaerobic treatments of these effluents were performed using a special laboratory reactor. Chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of effluents from different scouring processes were defined. The results of this study indicate that the anaerobic biological and chemical treatments of WSE treated by combined enzymatic-ultrasound scouring is a promising alternative technology from the point of view of reducing the wastewater pollution and the effective cleaning of effluents coming out from this process. Wool scouring effluent Aerobic treatment Anaerobic treatment Clean technology Activated-sludge Enzyme
Journal of Biomaterials and Nanobiotechnology, 2011
Scouring of raw wool is a chemical treatment that needs a high amount of detergents, alkalis and ... more Scouring of raw wool is a chemical treatment that needs a high amount of detergents, alkalis and water. Effluents produced by this treatment are extremely polluted with chemicals and impurities washed out from the fibers. It is well known that the ultrasound washing can remove effectively different substances from the textile surfaces even without surfactants due to the cavitations occurring at certain parameters of the ultrasound field. On the other side water treatments of wool combined with mechanical agitation provoked felting which can impair the quality of wool materials. Felting itself depends not only on the parameters of water treatments but also on the structure of wool cuticle. Partial hydrolysis of the cuticle with some proteases can decrease considerably the wool felting. The aim of this work is to study the possibility of applying the ultrasound at the process of raw wool scouring and the influence of proteases on the felting properties of wool at these conditions. It has been found out that ultrasound environment applied does not impair the specific activity of enzyme auxiliaries used and leads to increasing of their effect on the surface of wool fibers. Thus the scouring process studied could be used for developing of a technology producing lower amount and less polluted effluents.
BioResources, 2007
Research on lignin biodegradation has become of great interest, due to the fact that lignin is on... more Research on lignin biodegradation has become of great interest, due to the fact that lignin is one of the most abundant renewable materials, next to cellulose. Lignin is also the substance that gives color to raw flax fibers. In order to bleach the flax and to keep its tenacity high enough for textile applications, it is necessary to remove the lignin and partially to preserve the pectin. Lignin and pectin are the main constituents of the layer which sticks the flax cells together within the multicellular technical fiber. White-rot fungi and their oxidative enzymes, laccases and peroxid-ases (lignin peroxidases and manganese peroxidases), are being applied for the biobleaching of papermaking pulp, thereby reducing the need for environmentally harmful chemicals. Some data also suggest that it is possible to use other phenolytic enzymes, such as pure laccase, for this purpose. The objective of the present work was to study the possibility of bleaching flax fibers by pure laccase and c...
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2008
The investigations aim at revealing the ability of a 1,8-napthalimide-modified poly(amidoamine) d... more The investigations aim at revealing the ability of a 1,8-napthalimide-modified poly(amidoamine) dendrimer from second generation to respond to the presence of cuprum cations and protons in the environment. It has been established that a single Cu 2+ cation present in the dendrimer molecule is capable of quenching more than 78% of its fluorescence what is an indication of high sensitiveness. An enhancement of the fluorescence emission of the dendrimer has been observed in acidic medium. It has been established that the processes of coordinating the ions in different sites of the dendrimer are reversible.
Macromolecular Materials and Engineering, 2002
Macromolecular Materials and Engineering, 2003
Journal of Applied Polymer Science, 2001
The copolymerization of styrene or methyl methacrylate with 1,8‐naphthalimide dyes to yield fluor... more The copolymerization of styrene or methyl methacrylate with 1,8‐naphthalimide dyes to yield fluorescent side‐group copolymers was investigated. During copolymerization, no changes occurred in the chromophoric systems of the dyes. Colorimetrically, it was found that more that 0.90% of the dyes were chemically bonded to the polymer chain. The effect of polymer coloration was proven by appropriate coloristic characterization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2463–2470, 2001
International Journal of Clothing Science and Technology, 1999
In this study the effect of the aminofunctional silicone softeners on fabrics’ heat and moisture ... more In this study the effect of the aminofunctional silicone softeners on fabrics’ heat and moisture transport properties has been investigated by means of Alambeta and Permetest instruments. The silicone treated PES blended fabrics are warmer to the touch, but less comfortable as regards their reduced water‐vapour permeability. The finishing stage of the fabrics has considerable influence on their thermal touch sensation and water‐vapour permeability.